Stop 6: Meuwissen Creek
Stop 6: Meuwissen Creek
Our next stop is within sight as we head toward the entrance of Meuwissen Lake, which feeds into Benton Lake via a small stream you will see very soon. Feel free to head into the stream and paddle down it. Keep an eye on the water depth, as it gets pretty shallow in there. At the end of the stream is another fish barrier, with electrical sensors that help volunteers catch carp coming into this stream to spawn. These sensors are cutting-edge and help fight the invasive carp issue .
Over the past few years, Benton Lake has been threatened by the growth of the invasive carp population. They are bottom feeders, which means they eat plants and animals from the bottom of the lake. This turns up all the soil, muddling the waters and putting nutrients back into the water from the soil. The excess nutrients and muddy water then prevents sunlight from entering the water, causing fewer aquatic plants to grow. Native aquatic plants are key to maintaining good water quality in a lake, and provide vital habitat for waterfowl and other wildlife. Without them both water quality and wildlife will degrade.
A single female carp can spawn up to 3 million eggs a season, which hatch within a week of being laid. They will go to a shallow spot within a lake or marsh and lay their eggs in this location. In the case of Benton Lake, most carp spawn in Meuwissen Lake. This area is thus a key focus in the efforts to remove and manage carp in Benton Lake. Removing carp from this area is easier than from the middle of the lake.
Natural factors that limit the population of carp include a balanced lake ecosystem. Predator fish will prey upon common carp, while some pan fish such as bluegills will feed upon the carp eggs. When this balance is off, it will lead to conditions that favor carp over other fish. One effect is the reduction in aquatic plants. This leads to more suspended solids in the water, further decreasing aquatic plants by blocking sunlight, and also increasing the water temperature that decreases dissolved oxygen that other fish need to survive. The reduction in plant growth then leads to more nutrients in the water causing algal blooms. The algal blooms contribute to the growth of the carp population and the decline of the native fish and plant populations.
The Benton Lake Watershed Conservancy, in cooperation with Carver County and the City of Cologne, has made many efforts to combat the carp and eutrophication issues as they are inhibiting the use of the lake. In addition to the fish barriers, carp are actively removed every year by volunteers working in the lake. They use large nets and bait the carp with corn. The captured carp is then given to local anglers, buried in the ground and then composted. Yearly population surveys of all fish within the lake are conducted to track the progress of the carp project and track that the native species are thriving.
The cattails and other plants surrounding this stream are fantastic places for birds to rest. Plants like cattails and pencil reeds are semi-aquatic, which means they put their roots in the water while the rest of the plant is exposed to the atmosphere. The cattail part of said plant is the flowering body of the plant, which turns into the signature brown corn dog after the male parts of the flower fly off the plant. Each part of the cattail plant has a function as it can be used for food, shelter, fire, and medicine.
Look for birds like the Red-winged Blackbird, the Wood Duck, and the Chickadee as we travel down this stream toward Meuwissen Lake. You will also see some fish in the shallow water as long as the algal blooms are not too large. Many other birds live and hunt in the lake, including the American Bald Eagle, the Canada Goose, the Pelican, and some Trumpeter Swans. These birds hunt fish and other animals. Larger birds, such as the Bald Eagle and the Pelican, feed mostly on fish. Smaller birds like the red-winged blackbird will eat beetles, insect larvae, and waterbugs that they can find on plants or the surface of the water. All of these birds will benefit from the restoration of the lake by the Benton Lake Watershed Conservancy and Carver County Water Management Organization.
The BLWC was created around a decade ago when a young man named Jacob Steinbauer was looking for fish in Benton Lake using an underwater camera. He realized he couldn’t see underwater and wanted to clean up the lake for people who enjoy it. Working with Don Smith, a retired gentleman who has lived on the lake for many years, the two created the Benton Lake Watershed Conservancy. They met with the city council to raise awareness about the issue surrounding the lake. During the early stages of the project, they contacted the Minnesota Department of Natural Resources to let them know about their concerns. With this increased awareness about the issues within the lake, the DNR was able to provide funding for the restoration project. Since then, many other projects have been carried out such as carp nets, fish population surveys, and winter aeration. The work done by these gentlemen with the BLWC has already benefited the lake, and they hope to see more improvements each year.
Benton Lake was previously home to fish that thrived in clean water, such as Northern Pike and Sunfish. There are now more Carp, bullheads, and suckers, fish that do well in dirty waters and feed along the bottom of the lake. As the community works together to restore the lake’s cleanliness, the fish that thrive in cleaner waters have started to return. There is still more work to be done, however, and more awareness is needed for the lake to return to how it was many years ago. Conservation efforts have grown every year. Fish population surveys, electrical sensors, fish barriers, and volunteer carp catching all help the quality of Benton Lake.
When driving down Highway 212, you might notice a building just off the road, west of Cologne. That is the Cologne Wastewater Treatment Plant. Most cities the size of Cologne or bigger have wastewater treatment facilities or send their household waste to a larger facility that works with multiple cities. Wastewater from homes, restaurants, and businesses in Cologne travels to the plant, where it is purified. When water arrives at the plant, it goes through a primary treatment that removes floatable solids and larger suspended solids. After this, the water flows through filters that use bacteria to clean the water. Then it gets disinfected so it may safely return to the ecosystem. In the case of Cologne, the water comes out into the creek connecting Meuwissen and Benton Lakes. This water is safe for plants and animals to use, as the Minnesota Pollution Control Agency gets reports from the City of Cologne each month and declares the water safe.
Even though the water leaving the treatment plant meets the requirements for safety from the Minnesota Pollution Control Agency, even more research is being done to improve its quality. For example: in 2023, the Carver County Water Management Organization worked with the Benton Lake Watershed Conservancy to install several biochar logs near the outlet of the treatment plant. These biochar logs help trap excess nutrients to purify further the water coming out of the plant. All these steps are crucial to cleaning the wastewater generated by Cologne and allowing it to re-enter the water cycle.
You may be seeing a lot of algae on the lake’s surface as you paddle around today, so I’ll take a moment to give you the algal basics. Algae generates 70% of Earth's atmospheric oxygen! It was even the first organism to do so, back when this entire place was a pile of rocks, sludge, and formless ooze. This process of turning Carbon dioxide and water into energy and oxygen using solar energy is called photosynthesis. It is integral to plants, animals, and pretty much everything else.
Algae is also the leading food source for animals on our planet. Ever heard of a whale? These animals eat tons and tons of algae per year, even though the algae themselves are so small. That doesn’t mean you should eat algae right from the water, though. There are ways humans can use algae, such as creating food from algae, using it as fuel, and as a research subject, as there are more than 10 million species of algae. Ingredients like algal flour and algal oils are all present in supermarkets today.
Despite algae overgrowth due to eutrophication being a problem in lakes such as Benton Lake, algae benefits every form of life on Earth. Everything needs algae to survive, but just like any resource, it is possible to have too much of it. When it completely covers the surface of a water body, the amount of light and oxygen that reaches underwater plants and animals is severely reduced, which causes an underdeveloped ecosystem. As with all things in nature, balance is the goal.
